Answer

PROBLEM

The GFI MailEssentials installation (or upgrade) is failing because the Microsoft Exchange 2013 Backend Role is missing, although Microsoft Exchange 2013 is not even installed.
 

ENVIRONMENT

• GFI MailEssentials 2015
• All supported environments

SOLUTION

1. Open the registry editor and navigate to the following key:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15
2. Rename the above key to´HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15--´ (or similar)
3. Run the GFI MailEssentials Installer again
4. After a successful installation of GFI MailEssentials change the key back to ´HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v15´

CAUSE

Previously Microsoft Exchange 2013 Preview was installed on the server, but after removal the registry key was left behind. The GFI MailEssential installer detects the key and looks for the Microsoft Exchange 2013 components on the system.